Gold alloy wire for bonding wire having high initial bondability, high bonding reliability, high  roundness of compression ball, high straightness, high resin flowability resistance, and low specific resistance

ABSTRACT

There are provided a gold alloy wire for a bonding wire having high initial bonding ability, high bonding reliability, high roundness of a compression ball, high straightness, high resin flowability resistance, and low specific resistance. The gold alloy wire having high initial bonding ability, high bonding reliability, high roundness of a compression ball, high straightness, high resin flowability resistance, and low specific resistance contains one or more of Pt and Pd of 500 to less than 1000 ppm in total, Ir of 1 to 100 ppm, Ca of more than 30 to 100 ppm, Eu of more than 30 to 100 ppm, Be of 0.1 to 20 ppm, if necessary, one or more of La, Ba, Sr, and Bi of 30 to 100 ppm in total, if necessary, and a balance being Au and inevitable impurities.

CROSS-REFERENCE TO PRIOR APPLICATION

This is a U.S. National Phase Application under 35 U.S.C. §371 ofInternational Patent Application No. PCT/JP2006/311525 filed Jun. 8,2006, which claims the benefit of Japanese Patent Application No.2005-173726 filed Jun. 14, 2005. Both of them are incorporated byreference herein. The International Application was published inJapanese on Dec. 21, 2006 as WO 2006/134825 A1 under PCT Article 21(2).

TECHNICAL FIELD

The present invention relates to a gold alloy wire for a bonding wirethat is used to connect a chip electrode of a semiconductor element suchas a transistor, LSI, or IC to an external lead part and has highinitial bonding ability, high bonding reliability, high roundness of acompression ball, high straightness, high resin flowability resistance,and low specific resistance. In particular, the invention relates to agold alloy wire for wire bonding that can be used in a wide temperaturerange from low temperature to high temperature (for example, in therange of −20 to 60° C.) and has a diameter less than 20 μm.

BACKGROUND ART

An ultrasonic wave combined thermal compression bonding is performed fora gold alloy wire for a bonding wire in order to connect an electrode onan IC chip to an external lead part. A gold alloy wire having thefollowing composition has been known as a gold alloy wire for a bondingwire used in this case. The composition of the gold alloy wire includesat least one of Pd, Pt, Rh, Ir, Os, and Ru of 3 to 1000 ppm, Eu of 1 to30 ppm, at least one of Be, Ca, Ge, and Sr of 1 to 30 ppm, and a balancebeing Au and inevitable impurities (see Japanese Unexamined PatentApplication, First Publication No. Hei 08-109425.)

SUMMARY OF THE INVENTION

Recently, as the integration of the semiconductor elements hasincreased, an Al pad area becomes small and a substrate having a lowheat resistance has been used. As a result, it is required to obtainexcellent initial bonding ability (resistance in separation ofcompression balls from the Al pad during the bonding of balls onto theAl pad) with a lower temperature and smaller area than those of therelated art.

In addition, the decrease of bonding strength due to a ball bonding orthe occurrence of bonding failures due to a rise of electricalresistance in the bonding interface has caused problems in an automobileIC for requiring a high reliability at the severe use environments of ahigh-temperature and a high frequency IC in which the operatingtemperature is increased. Since the bonding failure is apt to graduallyoccur due to the deterioration of bonding conditions, such as a lowtemperature joint or a shrinking of the bonding areas, it is required toensure the bonding reliability (persistence of the bonding strength orelectrical resistance due to the ball bonding in the bonding interfaceat some environments) higher than that of the related art.

In addition, the roundness of the compression balls is low at the ballbonding, a portion of the compression balls are protruded from the Alpad, and a short failure occurs by the contact of a neighboringcompression ball. Since the contact failure is increasingly apt to occurby the shrinking of the Al pad area and a bonding pad pitch, it isrequired that the roundness of the compression ball is higher than thatof the related art compression ball.

Furthermore, meanwhile, at the same time the length of a wire loop(hereinafter, referred to as a loop length) for joining the chipelectrodes of the semiconductor devices to the outer lead becomes long,the distance between the wire loop and a neighboring loop parallel tothe wire loop becomes narrow. In order to cope with the above-describedstates, it is required to make the diameter of the gold alloy wire usedas a bonding wire increasingly thin. However, when the diameter of thegold alloy wire is reduced, when the coiled gold alloy wire is extractedfrom a spool, a curling or meandering (curvature or bending) may easilyoccur in the gold alloy wire. When the bonding is conducted by using thegold alloy wire in which the curling or meandering (curvature orbending) exists, since the neighboring bonding wire contacts and a shortoccurs, the bad semiconductor chips are produced to reduce the yieldratio. More particularly, when the diameter of the bonding wire made ofthe gold alloy is less than 20 μm, the curling or meandering (curvatureor bending) may easily occur in the wire directly after being unreeledfrom the spool. The property of which the loop formed by the bondingwithout the occurrence of the curling or meandering (curvature orbending) in the wire directly after being unreeled from the spool doesnot contact to the neighboring loop is referred to as the straightness.When the straightness is insufficient, since the loop contacts to theneighboring loop and shorts out, the bad semiconductor devices areproduce to reduce the yield ratio.

In addition, the loop is formed by bonding the wire, and then beingmolded by the resin. However, at this time, when the bonding wire isinfluenced by the resin, since the bonding wire contacts to theneighboring loop and shorts out, the bad semiconductor devices areproduced to reduce the yield ratio. With respect to the resin flow, whenthe diameter of the related art gold alloy wire for the bonding wire is25 μm or 30 μm, the resin flow is hardly problem. However, as the highintegration of the semiconductor devices increases, the distance of thechip electrodes of the semiconductor devices becomes narrow. In order tocope with the high integration of the semiconductor devices, the bondingis performed by using the wire having the thin diameter. However, whenthe wire diameter is less than 20 μm, the loop is easily influencedduring the molding of the resin. Accordingly, it is necessary to havethe property (hereinafter, referred to as resin flowability resistance)of which the resin flow is difficult to produce, even though the wirehas a thin diameter.

Even though a gold alloy wire for the bonding wire in which theabove-mentioned severe conditions are improved is obtained, theresistance of the gold alloy wire is desirable so as to be low in termsof heat or high frequency driving. In particular, as described above, asthe integration of the semiconductor elements has increased, thediameter of the gold alloy wire becomes smaller and a loop becomeslonger. As a result, the resistance of the gold alloy wire tends to belong. Therefore, there has been a demand for a gold alloy wire for abonding wire that has a low specific resistance and satisfies theabove-mentioned characteristics.

For the above-mentioned difficult demand, the gold alloy wire for thebonding wire described in patent reference 1 has problems in that a workhardening ability of a free-air ball is low and initial bonding abilityis low. For this reason, it has not been possible to obtain a gold alloywire for a bonding wire that can cope with the recent above-mentioneddemand. An object of the invention is to provide a more excellent goldalloy wire for a bonding wire having high initial bonding ability, highbonding reliability, high roundness of a compression ball, highstraightness, high resin flowability resistance, and low specificresistance.

The inventors have done research so as to develop a gold alloy wire fora bonding wire having high initial bonding ability, high bondingreliability, high roundness of a compression ball, high straightness,high resin flowability resistance, and low specific resistance. Theresults obtained by the research are as follows:

(A) A gold alloy wire has a component composition having one or more ofPt and Pd of 500 to less than 1000 ppm in total, Ir of 1 to 100 ppm, andCa of more than 30 to 100 ppm and Eu of more than 30 to 100 ppm, whichare more than those of the gold alloy wire for the bonding wire in therelated art in a high-purity gold having purity of 99.999% by mass. Theabove gold alloy wire has high initial bonding ability, high bondingreliability, high roundness of a compression ball, high straightness,high resin flowability resistance, and low specific resistance.

(B) The gold alloy wire having the composition described in (A) furtherhas Be of 0.1 to 20 ppm. Since Be distorts a crystal lattice of Au toincrease the mechanical strength of the gold alloy wire for the bondingwire and the work hardening ability of a free-air ball and lowers are-crystallizing temperature, it is possible to raise the height of aloop. As a result, since it is possible to obtain the proper height of aloop, Be can be added, if necessary.

(C) The gold alloy wire having the composition described in (B) furtherincludes one or more of La, Ba, Sr, and Bi of 30 to 100 ppm in total.Since the mechanical strength of the gold alloy wire for the bondingwire and the work hardening ability of a free-air ball are increased anda re-crystallizing temperature is raised in the gold alloy wire, it ispossible to reduce the height of loop of the gold alloy wire.

(D) Even though Ag of 1 to 10 ppm is contained in the gold alloy wirethat is described in (A) to (C) and has high initial bonding ability,high bonding reliability, high roundness of a compression ball, highstraightness, high resin flowability resistance, and low specificresistance, it has little influence on the properties.

The invention based on the above-described research results is asfollows:

(1) A gold alloy wire for a bonding wire having high initial bondingability, high bonding reliability, high roundness of a compression ball,high straightness, high resin flowability resistance, and low specificresistance has a component composition having one or more of Pt and Pdof 500 to less than 1000 ppm in total, Ir of 1 to 100 ppm, Ca of morethan 30 to 100 ppm, Eu of more than 30 to 100 ppm, and a balance beingAu and inevitable impurities.

(2) A gold alloy wire for a bonding wire having high initial bondingability, high bonding reliability, high roundness of a compression ball,high straightness, high resin flowability resistance, and low specificresistance has a component composition including one or more of Pt andPd of 500 to less than 1000 ppm in total, Ir of 1 to 100 ppm, Ca of morethan 30 to 100 ppm, Eu of more than 30 to 100 ppm, Be of 0.1 to 20 ppm,and a balance being Au and inevitable impurities.

(3) A gold alloy wire for a bonding wire having high initial bondingability, high bonding reliability, high roundness of a compression ball,high straightness, high resin flowability resistance, and low specificresistance has a component composition having one or more of Pt and Pdof 500 to less than 1000 ppm in total, Ir of 1 to 100 ppm, Ca of morethan 30 to 100 ppm, Eu of more than 30 to 100 ppm, Be of 0.1 to 20 ppm,one or more of La, Ba, Sr, and Bi of 30 to 100 ppm in total, and abalance being Au and inevitable impurities.

(4) The gold alloy wire having high initial bonding ability, highbonding reliability, high roundness of a compression ball, highstraightness, high resin flowability resistance, and low specificresistance described in any one of (1) to (3) may further includes Ag of1 to 10 ppm. In a method of manufacturing a gold alloy wire for abonding wire for annealing gold alloy wire materials obtained byconducting a drawing process the gold alloy wire materials having thecomponent compositions described in (1) to (4) so as to have apredetermined diameter, when 0.2% proof strength (Pa) of the gold alloywire for the bonding wire is σ_(0.2), Young's modulus (Pa) is E, andfracture elongation percentage is E_(L), it may manufacture the goldalloy wire for the bonding wire satisfying the following equations underan annealing temperature of 550° C. or less which is lower than therelated art annealing temperature:

E≧75 GPa,

(σ_(0.2) /E)≧2.2×10⁻³, and

2%≦E_(L)≦10%

It is more preferable that a reduction ratio by one die during thedrawing process is 5% or less which is lower than the related artreduction ratio. The gold alloy wire for the bonding wire for satisfyingthe above-described conditions has higher straightness and higher resinflowability resistance.

Accordingly, according to the invention,

(5) when 0.2% proof strength (Pa) of the gold alloy wire for the bondingwire is σ_(0.2), Young's modulus (Pa) is E, and fracture elongationpercentage is E_(L), the gold alloy wire having high initial bondingability, high bonding reliability, high roundness of a compression ball,high straightness, high resin flowability resistance, and low specificresistance described in any one of (1) to (4) satisfies the followingequations:

E≧75 GPa,

(σ_(0.2) /E)≧2.2×10⁻³, and

2%≦E_(L)≦10%

Hereinafter, the reason why the component composition of the gold alloywire for the bonding wire according to the invention having high initialbonding ability, high bonding reliability, high roundness of acompression ball, high straightness, high resin flowability resistance,and low specific resistance is limited as described above will beexplained.

[I] Component Composition

(a) Pt and Pd:

Both Pt and Pd, which form a complete solid solubility with Au, causethe deterioration of the bonding strength of the compression ball and Alpad to inhibit and improve the bonding reliability. The layered-shapephase including Pt or Pd is formed in the vicinity of a bondinginterface to act as a layer (so called, barrier layer with respect to Audiffusion) for decreasing a diffusion velocity of Au, thereby inhibitingthe generating velocity of voids generating in the bonding part inaccordance with the diffusion of Au. Accordingly, it is considered thatPt and Pd inhibit the deterioration of the bonding strength of thecompression ball and Al pad and improve the bonding reliability. As theamount of Pt or Pd is rich, the effect for inhibiting (improving thebonding reliability) the deterioration of the bonding strength growshigher. However, when the total amount of one or more of Pt and Pd isless than 500 ppm, the effect for inhibiting the deterioration of thebonding strength is not obtained. Meanwhile, when the total amount ofone or more of Pt and Pd is larger than 1000 ppm, the resistance of thegold alloy is raised. For this reason, it is not preferable that thetotal amount of one or more of Pt and Pd be less than 500 ppm or 1000ppm or larger. Accordingly, the total amount of one or more of Pt and Pdis set within the range of 500 to less than 1000 ppm.

(b) Ir:

Ir inhibits the growth of grains (coarsening of grains). For thisreason, when forming a free-air ball, it prevents the grain of a wirepart (heat-affected part) directly on the ball from being coarsened dueto the effect of heat on the ball, and the solidified free-air ball isformed from a great number of fine grains. In addition, the compressionball evenly extends in a radial pattern, and the roundness of thecompression ball is improved. However, when the amount of Ir is lessthan 1 ppm, it may not obtain a predetermined effect. Meanwhile, whenthe amount of Ir is larger than 100 ppm in the gold alloy wire for thebonding wire containing one or more of Pt and Pd of 500 to less than1000 ppm in total, the effects are saturated and are not apparentlyimproved, thus causing IC chips to destruct or impair. For this reason,it is not preferable that the amount of Ir be less than 1 ppm and largerthan 100 ppm. Accordingly, the amount of Ir is set within the range of 1to 100 ppm.

(c) Ca:

Ca which is an alkali earth metal and has the metal bond radius largerthan that of Au distorts the crystal lattice of Au, thereby increasingthe mechanical strength of the gold alloy wire for the bonding wire andwork hardening ability of the free-air ball, raising there-crystallizing temperature, and lowering the height of loop of thegold alloy wire. However, when the amount of Ca is less than 30 ppm,since the work hardening ability is lowered, thereby lowering theinitial bonding ability. In addition, the strength is low, it isdifficult to satisfy the conditions of E≧75 GPa, (σ_(0.2)/E)≧2.2×10⁻³,and 2%≦E_(L)≦10%. Therefore, the straightness and resin flowabilityresistance are lower. Meanwhile, when the amount of Ca is larger than100 ppm, a quantity of oxides is generated on the surface of a free-airball during the bonding of balls, and large shrinkage holes, which donot contribute to the bonding, are formed at the bottom-center of thefree-air ball. Since the initial bonding ability of the ball bonding islowered, it is not preferable that the amount of Ca be 30 ppm or less orlarger than 100 ppm. Accordingly, the amount of Ca is set within therange of more than 30 to 100 ppm.

(d) Eu:

Eu which is a rare earth metal and has the metal bond radius larger thanthat of Au distorts the crystal lattice of Au, thereby increasing themechanical strength of the gold alloy wire for the bonding wire and thework hardening ability of free-air ball, raising the re-crystallizingtemperature, and lowering the height of loop of the gold alloy wire. Inaddition, since Eu has a metal bonding radius significantly larger thanother metals, the above-mentioned effect is significant in the goldalloy wire for the bonding wire having a small diameter (in particular,diameter less than 20 μm). However, when the amount of Eu is 30 ppm orless, the work hardening ability is lowered, thereby lowering theinitial bonding ability. Further, since the strength is lower, it isdifficult to satisfy the conditions of E≧75 GPa, (σ_(0.2)/E)≧2.2×10⁻³,and 2%≦E_(L)≦10%. Therefore, the straightness and resin flowabilityresistance are lower. Meanwhile, when the amount of Eu is larger than100 ppm, a quantity of oxides is generated on the surface of free-airball during the bonding of balls, and large shrinkage holes, which donot contribute to the bonding, are formed at the bottom-center of thefree-air ball. Since the initial bonding ability of the ball bonding islowered, it is not preferable that the amount of Eu be 30 ppm or lessand larger than 100 ppm. Accordingly, the amount of Eu is set within therange of more than 30 to 100 ppm.

(e) Be:

Be has the metal bond radius smaller than that of Au and distorts thecrystal lattice of Au, thereby increasing the mechanical strength of thegold alloy wire for the bonding wire and the work hardening ability offree-air ball. In a case of containing Be together with Ca and Eu, sincethe re-crystallizing temperature lowers and the height of loop rises torealize the proper height of loop, it is possible to add, if necessary.However, when the amount of Be is less than 0.1 ppm, it may not obtain apredetermined effect. Meanwhile, when the amount of Be is larger than 20ppm, a quantity of oxides is generated on the surface of free-air ballduring the bonding of balls, large shrinkage holes, which do notcontribute to the bonding, are formed at the bottom-center of thefree-air ball. Accordingly, the initial bonding ability of the ballbonding is lowered and the size of grains of the directly upper part ofball and the ball part increases, thus deteriorating the roundness ofthe compression ball part. For this reason, it is not preferable thatthe amount of Be be less than 0.1 ppm and larger than 20 ppm.Accordingly, the amount of Be is set within the range of 0.1 to 20 ppm.

(f) La, Ba, Sr, and Bi:

La which is a rare earth metal, Ba and Sr which are alkali earth metals,and Bi which is in a 5B group of the periodic system are possible toadd, if necessary, in order to increase the mechanical strength of thegold alloy wire for the bonding wire and the work hardening ability offree-air ball, raise the re-crystallizing temperature, and lower theheight of loop of the gold alloy wire. However, even though the amountof at least one of La, Ba, Sr, and Bi is less than 30 ppm, it may notobtain a predetermined effect. Meanwhile, when the amount of at leastone of La, Ba, Sr, and Bi is larger than 100 ppm, a quantity of oxidesis generated on the surface of free-air ball during the bonding ofballs, and large shrinkage holes, which do not contribute to thebonding, are formed at the bottom-center of the free-air ball.Accordingly, the initial bonding ability of the ball bonding is lowered.For this reason, it is not preferable that the amount of at least one ofLa, Ba, Sr, and Bi be less than 30 ppm and larger than 100 ppm.Accordingly, the amount of at least one of La, Ba, Sr, and Bi is setwithin the range of 30 to 100 ppm.

(g) Ag:

Even though Ag of 1 to 10 ppm is contained, it has little influence onthe properties. Accordingly, Ag is added, if necessary. However, whenthe amount of Ag is over 10 ppm, the initial bonding ability tends to belowered. Therefore, it is not preferable that the amount of Ag be over10 ppm.

[II] Mechanical Property

All of the gold alloy wires for the bonding wire containing theabove-described component composition have high initial bonding ability,high bonding reliability, high roundness of a compression ball, highstraightness, high resin flowability resistance, and low specificresistance. However, when manufacturing the gold alloy wire for thebonding wire so as to satisfy the conditions of E≧75 GPa,(σ_(0.2)/E)≧2.2×10⁻³, and 2%≦E_(L)≦10% by defining 0.2% proof strength(Pa) of the gold alloy wire as σ_(0.2), Young's modulus (Pa) as E, andfracture elongation percentage as E_(L), all of the gold alloy wires forthe bonding wire containing the above-described component compositionhave higher straightness and higher resin flowability resistance.

The reason is as follows;

In a case of E<75 GPa, that is, when the Young's modulus is low, thebonded gold alloy wire largely flows by the resin (that is, the resinflow is large) during the molding after the wire bonding, thereby thecontact frequency and short frequency of the gold alloy wires adjacentto each other increase. Therefore, the yield ratio of semiconductorchips is reduced. When σ_(0.2)/E is 2.2×10⁻³ and more, the straightnessrapidly is improved, and when the fracture elongation percentage is lessthan 2%, the residual distortion of the gold alloy wire after drawingthe wire resides after annealing and the straightness is low. Inaddition, when the fracture elongation percentage is higher than 10%,Most of them satisfies the conditions of E<75 GPa and(σ_(0.2)/E)<2.2×10⁻³. Therefore, the straightness is reduced or theresin flow increases.

According to the invention, the fracture elongation percentage E_(L)(%), the 0.2% proof strength σ_(0.2) (Pa), and the Young's modulus (Pa)of the gold alloy wire for the bonding wire are measured by tensioningthe gold alloy wire up to be fractured by a tension tester in theconditions of the distance between gauge points: 100 mm and a tensionvelocity: 10 mm/minute at a room temperature.

Here, strain and tension stress are defined as follows. Strain=theelongation (mm) of the gold alloy wire for the bonding wire/100 mm, andtension stress (Pa)=tension load (N)/initial sectional area (m²) of thegold alloy wire for the bonding wire. In addition, the fractureelongation percentage E_(L) (%), the 0.2% proof strength σ_(0.2) (Pa),and the Young's modulus (Pa) are defined as follows. The fractureelongation percentage E_(L) (%)=strain when the gold alloy wire isfractured×100 [elongation (mm) when the gold alloy wire is fractured/100(mm)] 1×100. The 0.2% proof strength σ_(0.2) (Pa): tension stress (Pa)in applying a permanent deformation of 0.2% to the gold alloy wire forthe bonding wire. In addition, the Young's modulus (Pa):the ratio oftension stress and strain, that is, tension stress (Pa)/strain, in therange where tension stress and strain are in direct proportion.

As described above, the gold alloy wire for the bonding wire accordingto the invention has excellent initial bonding ability, excellentbonding reliability, excellent roundness of a compression ball,excellent straightness, excellent resin flowability resistance, and lowspecific resistance. Accordingly, when the gold alloy wire is used inbonding processes, it is possible to improve the yield ratio ofsemiconductor devices. As a result, the gold alloy wire for the bondingwire according to the invention has especially excellent effects in anindustry.

DETAILED DESCRIPTION OF THE INVENTION

A gold alloy wire having a wire diameter: 19 μm was manufactured by adrawing process a gold alloy wire material having a wire diameter: 50 μmand having component compositions indicated in Tables 1 to 3 at areduction ratio by one die of 4.8%. Further, gold alloy wires for abonding wire according to the invention (hereinafter, referred to aswires according to the invention) 1 to 34, comparative gold alloy wiresfor a bonding wire (hereinafter, referred to as comparative wires) 1 to20, and the related art gold alloy wire for a bonding wire (hereinafter,referred to as the related art wire) 1 were manufactured by annealingthe gold alloy wire at temperature indicated in Tables 4 to 6, andtaken-out by an immediate spool of radius: 50 mm. Here, in the annealingand winding process, the radii of all of sheaves (pulleys) using forchanging paths of the wires are 9 mm. A fracture elongation percentageE_(L), Young's modulus (Pa) E, and 0.2% proof strength (Pa) σ_(0.2) weremeasured by winding by a spool having a radius of 25 mm by 2000 m thewire taken-out by the immediate spool and removing the tip of the wireby 15 m, and σ_(0.2)/E was calculated. The results were indicated inTables 4 to 6. Further, the specific resistances of the wires aremeasured, and the results of the measurement were indicated in Tables 4to 6. The number of samples is five in each of the measurement, therebyobtaining an average value. Resistances (Ω) of the samples were measuredby a digital multimeter in the conditions of the distance between gaugepoints: 500 mm at a room temperature, and the specific resistances ofthe wires were obtained with the following equation.

Specific resistance (μΩcm)=resistance (Ω)×cross-sectional area(cm²)/50(cm)×10⁶

The wires 1 to 34 according to the invention, the comparative wires 1 to20, and the related art wire 1 having the component compositionsindicated in Tables 1 to 3 and the mechanical properties indicated inTables 4 to 6 were set in wire bond (maxam plus) manufactured by Kulicke& Soffa, and the bonding was performed on the substrate in which ICchips of the semiconductor were mounted under the conditions of heatingtemperature: 150° C., the length of loop: 5 mm, the height of loop: 220μm, the diameter of a compression ball: 34 μm, and the height of thecompression ball: 8 μm. The straightness, initial bonding ability, androundness of the compression ball with respect to the wires 1 to 34according to the invention, the comparative wires 1 to 20, and therelated art wire 1 were estimated by following measurements.

Straightness Estimation:

10000 loops were manufactured at a pad pitch distance of 45 μm withrespect to each of the samples, and the number (contacting number) ofplaces for contacting between the neighboring loops was measured.Accordingly, the straightness was estimated by indicating the results inTables 4 to 6.

Initial Bondability Estimation:

10000 loops attached to each of the samples were manufactured, and thenumber (number of ball lifts) of times that the compression ball is notbonded to the Al pad during the bonding of balls was measured.Accordingly, the initial bonding ability was estimated by indicating theresults in Tables 4 to 6.

Compression Ball Roundness Estimation:

By observing 100 compression balls with respect to each of the samples,when all of them are good, it indicates as “◯”, and even though one badexists, it indicates as “x”. Accordingly, the roundness was estimated byindicating the results in Tables 4 to 6.

Bonding Reliability Estimation:

After holding for 1000 hours in air of 150° C., 100 proof tests withrespect to each sample were conducted by hanging a tool on a bendingpart (kink) of the loop directly on the compression ball. The fracturein the proof tests is referred to as a fracture (ball lift) in thebonding interface of the compression ball and Al pad. By observing thecompression balls, when all the fractures were occurred in a neck, itwas estimated as “◯”, and even though one ball lift exists, it wasestimated as “x”.

Further, the height of loop and the resin flowability resistance withrespect to the wires 1 to 34 according to the invention having thecomponent compositions indicated in Tables 1 to 3 and the mechanicalproperties indicated in Tables 4 to 6, the comparative wires 1 to 20,and the related art wire 1 were estimated.

Height of Loop:

The wires 1 to 34 according to the invention, the comparative wires 1 to20, and the related art wire 1 having the component compositionsindicated in Tables 1 to 3 and the mechanical properties indicated inTables 4 to 6 were set in the wire bond (maxam plus) manufactured byKulicke & Soffa, and the looping were mounted was performed under theconditions of the diameter of the compression ball: 34 m, the height ofthe compression ball: 8 μm, and the length of loop: 1 mm without doingreverse. The highest part of the loop and the height of the area of Alpad were measured by a light microscope, and the difference of thehighest part of the loop and the height of the area of Al pad wasobtained as the height of loop. Accordingly, the height of loop wasestimated by indicating the results in Tables 4 to 6.

Resin Flowability Resistance:

After sealing with an epoxy resin the substrate in which the bonded ICchips of the semiconductor were mounted under the condition of thelength of loop: 3.5 mm by using a molding apparatus, the inside of thesemiconductor chip was X-ray projected by using a soft X-raynon-destruction inspection system and the flowing rates where themaximum portion of the wire flow were measured at 20 times. By dividingthe average value of the measured flow rates by the length of loop, theobtained value (%) was defined as a resin flow, and the resin flow wasmeasured. Accordingly, the resin flowability resistance was estimated byindicating the results in Tables 4 to 6.

TABLE 1 Component Composition of Gold Alloy Wire (Mass ppm) Wire Pt PdIr Ca Be Eu La Ba Sr Bi Ag Au The 1 500 — 50 70 10 60 — — — — — Balancepresent 2 800 — 50 70 10 60 — — — — — Balance inven- 3 980 — 50 70 10 60— — — — — Balance tion 4 — 500 50 70 10 60 — — — — — Balance 5 — 800 5070 10 60 — — — — — Balance 6 — 980 50 70 10 60 — — — — — Balance 7 250250 50 70 10 60 — — — — — Balance 8 400 400 50 70 10 60 — — — — —Balance 9 490 490 50 70 10 60 — — — — — Balance 10 400 400 1 70 10 60 —— — — — Balance 11 400 400 100 70 10 60 — — — — — Balance 12 400 400 5032 10 60 — — — — — Balance 13 400 400 50 100 10 60 — — — — — Balance 14400 400 50 70 — 60 — — — — — Balance 15 400 400 50 70 20 60 — — — — —Balance 16 400 400 50 70 10 32 — — — — — Balance 17 400 400 50 70 10 100— — — — — Balance 18 400 400 50 70 10 60 30 — — — — Balance 19 400 40050 70 10 60 60 — — — — Balance 20 400 400 50 70 10 60 100 — — — —Balance

TABLE 2 Component Composition of Gold Alloy Wire (Mass ppm) Wire Pt PdIr Ca Be Eu La Ba Sr Bi Ag Au The 21 400 400 50 70 10 60 — 30 — — —Balance present 22 400 400 50 70 10 60 — 60 — — — Balance inven- 23 400400 50 70 10 60 — 100 — — — Balance tion 24 400 400 50 70 10 60 — — 30 —— Balance 25 400 400 50 70 10 60 — — 60 — — Balance 26 400 400 50 70 1060 — — 100 — — Balance 27 400 400 50 70 10 60 — — — 30 — Balance 28 400400 50 70 10 60 — — — 60 — Balance 29 400 400 50 70 10 60 — — — 100 —Balance 30 400 400 50 70 10 60 — — — — 1 Balance 31 400 400 50 70 10 60— — — — 5 Balance 32 400 400 50 70 10 60 — — — — 10 Balance 33 400 40050 70 10 60 — — — — — Balance 34 400 400 50 70 10 60 — — — — — BalanceCompara- 1  300* — 50 70 10 60 — — — — — Balance tive 2 1500* — 50 70 1060 — — — — — Balance 3 —  300* 50 70 10 60 — — — — — Balance 4 — 1500*50 70 10 60 — — — — — Balance 5  150*  150* 50 70 10 60 — — — — —Balance 6  750*  750* 50 70 10 60 — — — — — Balance *means a value outof the range of the present invention

TABLE 3 Component Composition of Gold Alloy Wire (Mass ppm) Wire Pt PdIr Ca Be Eu La Ba Sr Bi Ag Au Compara- 7 400 400 —* 70 10 60 — — — — —Balance tive 8 400 400 150* 70 10 60 — — — — — Balance 9 400 400 50  20*10 60 — — — — — Balance 10 400 400 50 120* 10 60 — — — — — Balance 11400 400 50 70  30* 60 — — — — — Balance 12 400 400 50 70 10  20* — — — —— Balance 13 400 400 50 70 10 120* — — — — — Balance 14 400 400 50 70 1060 120* — — — — Balance 15 400 400 50 70 10 60 — 120* — — — Balance 16400 400 50 70 10 60 — — 120* — — Balance 17 400 400 50 70 10 60 — — —120* — Balance 18 400 400 50 70 10 60 — — — — 20* Balance 19 400 400 5070 10 60 — — — — — Balance 20 400 400 50 70 10 60 — — — — — Balance TheRelated 400 400 50  20*  5  20* — — — — — — Art 1 *means a value out ofthe range of the present invention

TABLE 4 Mechanical Property The Annealing Fracture The Number ofRoundness Resin Height Tempera- Elongation Young's σ_(0.2)/ number ofball of Bonding flow- of Specific ture Percentage modulus E × σ_(0.2)contacts lifts Compression Reli- ability Loop resistance Wire (° C.)E_(L)(%) E(GPa) 10⁻⁵ (MPa) (Piece) (Piece) Ball ability (%) (μm) (μΩcm)The 1 525 4.1 89 2.4 217 19 0 ∘ ∘ 2.7 73 2.4 present 2 526 4.1 89 2.5226 18 0 ∘ ∘ 2.4 71 2.4 inven- 3 524 4.2 89 2.5 226 19 0 ∘ ∘ 2.6 75 2.4tion 4 524 4.2 89 2.5 219 21 0 ∘ ∘ 2.5 75 2.4 5 526 4.2 88 2.6 225 23 0∘ ∘ 2.7 73 2.4 6 525 4.1 88 2.4 211 18 0 ∘ ∘ 2.7 71 2.4 7 527 4.1 87 2.5222 22 0 ∘ ∘ 2.5 74 2.4 8 527 4.3 90 2.5 225 24 0 ∘ ∘ 2.7 74 2.4 9 5264.1 90 2.5 224 20 0 ∘ ∘ 2.6 75 2.4 10 527 4.3 86 2.5 218 23 0 ∘ ∘ 2.4 802.4 11 525 4.2 88 2.6 228 23 0 ∘ ∘ 2.4 75 2.4 12 513 4.1 80 2.3 184 30 0∘ ∘ 3.1 77 2.4 13 536 4.0 93 2.7 253 6 0 ∘ ∘ 2.2 69 2.4 14 536 4.2 892.5 222 21 0 ∘ ∘ 2.4 65 2.4 15 517 4.1 94 2.8 263 11 0 ∘ ∘ 2.1 85 2.4 16514 4.2 81 2.4 197 24 0 ∘ ∘ 2.6 79 2.4 17 534 4.3 93 2.8 262 7 0 ∘ ∘ 2.069 2.4 18 527 4.1 88 2.4 215 20 0 ∘ ∘ 2.4 72 2.4

TABLE 5 Mechanical Property The Annealing Fracture The Number ofRoundness Resin Height Tempera- Elongation Young's σ_(0.2)/ number ofball of Bonding flow- of Specific ture Percentage modulus E × σ_(0.2)contacts lifts Compression Reli- ability Loop resistance Wire (° C.)E_(L)(%) E(GPa) 10⁻⁵ (MPa) (Piece) (Piece) Ball ability (%) (μm) (μΩcm)The 19 530 4.1 93 2.7 248 10 0 ∘ ∘ 2.4 71 2.4 present 20 534 4.1 99 2.7270 14 0 ∘ ∘ 2.2 66 2.4 inven- 21 527 4.2 86 2.5 213 16 0 ∘ ∘ 2.3 71 2.4tion 22 531 4.1 92 2.7 248 19 0 ∘ ∘ 2.3 72 2.4 23 534 4.1 98 2.8 271 6 0∘ ∘ 2.0 68 2.4 24 527 4.1 89 2.5 224 19 0 ∘ ∘ 2.4 71 2.4 25 531 4.4 932.6 245 12 0 ∘ ∘ 2.4 69 2.4 26 534 4.3 97 2.8 276 7 0 ∘ ∘ 1.9 68 2.4 27527 4.2 89 2.6 227 18 0 ∘ ∘ 2.4 75 2.4 28 532 4.4 92 2.6 239 11 0 ∘ ∘2.1 70 2.4 29 535 4.3 96 2.8 269 10 0 ∘ ∘ 1.9 68 2.4 30 524 4.3 90 2.5224 22 0 ∘ ∘ 2.4 74 2.4 31 525 4.3 89 2.5 224 20 0 ∘ ∘ 2.6 75 2.4 32 5254.2 89 2.6 232 16 0 ∘ ∘ 2.5 74 2.4 33 485 2.0 99 3.0 296 31 0 ∘ ∘ 2.1 742.4 34 542 10.0 80 2.2 176 22 0 ∘ ∘ 3.2 72 2.4 Compara- 1 526 4.2 88 2.5220 18 0 ∘ x 2.4 75 2.3 tive 2 526 4.1 87 2.5 218 24 0 ∘ ∘ 2.7 71 2.5

TABLE 6 Mechanical Property The Annealing Fracture The Number ofRoundness Resin Height Tempera- Elongation Young's σ_(0.2)/ number ofball of Bonding flow- of Specific ture Percentage modulus E × σ_(0.2)contacts lifts Compression Reli- ability Loop resistance Wire (° C.)E_(L)(%) E(GPa) 10⁻⁵ (MPa) (Piece) (Piece) Ball ability (%) (μm) (μΩcm)Compara- 3 525 4.4 86 2.6 224 20 0 ∘ x 2.5 74 2.3 tive 4 526 4.3 89 2.6226 15 0 ∘ ∘ 2.6 75 2.5 5 526 4.3 86 2.5 212 17 0 ∘ x 2.5 75 2.3 6 5254.1 87 2.5 218 22 0 ∘ ∘ 2.3 71 2.5 7 524 4.2 87 2.5 212 19 0 x ∘ 2.4 822.4 8 526 4.2 87 2.5 221 A part of Al pad is damaged 2.4 9 516 4.4 782.1* 167 156 18 ∘ ∘ 4.3 83 2.4 10 535 4.3 94 2.7 254 7 5 ∘ ∘ 2.1 61 2.411 514 4.3 93 2.8 260 12 3 x ∘ 2.6 83 2.4 12 514 4.3 80 2.1* 171 121 15∘ ∘ 3.5 84 2.4 13 534 4.1 95 2.9 270 8 4 ∘ ∘ 2.1 61 2.4 14 535 4.0 992.8 275 12 3 ∘ ∘ 2.3 68 2.4 15 535 4.1 97 2.8 270 8 4 ∘ ∘ 2.0 70 2.4 16534 4.1 98 2.8 273 11 3 ∘ ∘ 1.9 67 2.4 17 536 4.0 98 2.7 265 7 3 ∘ ∘ 2.168 2.4 18 526 4.1 89 2.6 229 16 2 ∘ ∘ 2.5 73 2.4 19 305 1.5* 105  3.3345 258 0 ∘ ∘ 1.9 71 2.4 20 548 12.0*  74* 2.1* 158 171 0 ∘ ∘ 4.2 71 2.4The Related 515 4.3  74* 2.1* 158 382 45 ∘ ∘ 4.5 87 2.4 Art 1 *means avalue out of the range of the present invention

It can be understood from the results indicated in Tables 1 to 6 thatthe wires 1 to 34 according to the invention have low specificresistance, excellent straightness, initial bonding ability, roundnessof the compression ball, bonding reliability, and resin flowabilityresistance, and more particularly, with respect to the excellentstraightness, initial bonding ability, roundness of the compressionball, bonding reliability, and resin flowability resistance, thecomparative wires 1 to 20 and the related art wire 1 have a defect of atleast one of the above-described properties.

1. A gold alloy wire for a bonding wire that has high initial bondingability, high bonding reliability, high roundness of a compression ball,high straightness, high resin flowability resistance, and low specificresistance, the gold alloy wire comprising: a component compositioncomprising one or more of Pt and Pd of 500 to less than 1000 ppm intotal, Ir of 1 to 100 ppm, Ca of more than 30 to 100 ppm, Eu of morethan 30 to 100 ppm, and a balance being Au and inevitable impurities. 2.A gold alloy wire for a bonding wire that has high initial bondingability, high bonding reliability, high roundness of a compression ball,high straightness, high resin flowability resistance, and low specificresistance, the gold alloy wire according to claim 1, wherein the:component composition further comprises Be of 0.1 to 20 ppm.
 3. A goldalloy wire for a bonding wire that has high initial bonding ability,high bonding reliability, high roundness of a compression ball, highstraightness, high resin flowability resistance, and low specificresistance, the gold alloy wire according to claim 1, wherein the:component composition further comprises Be of 0.1 to 20 ppm, and one ormore of La, Ba, Sr, and Bi of 30 to 100 ppm in total.
 4. The gold alloywire for the bonding wire that has high initial bonding ability, highbonding reliability, high roundness of a compression ball, highstraightness, high resin flowability resistance, and low specificresistance according to claim 1, further comprising: Ag of 1 to 10 ppm.5. The gold alloy wire for the bonding wire that has high initialbonding ability, high bonding reliability, high roundness of acompression ball, high straightness, high resin flowability resistance,and low specific resistance according to claim 1, wherein, when 0.2%proof strength (Pa) of the gold alloy wire for the bonding wire isσ_(0.2), Young's modulus (Pa) is E, and fracture elongation percentageis E_(L), the following equations are satisfiedE≧75 GPa;(σ_(0.2) /E)≧2.2×10⁻³; and2%≦E_(L)≦10%.